#include <iostream>
#include<math.h>
#include<iomanip>
using namespace std;

int main() {
    
    int n;
    cin>>n;
    double* arr = new double[n];
    double sum = 0;
    for (int i = 0; i < n; i++)
    {
        cin >> arr[i];
        sum += arr[i];
    }
    double avg = sum / n,s=0;

    for (int i = 0; i < n; i++)
    {
        s += (arr[i] - avg) * (arr[i] - avg);
    }
    s = sqrt(s/n);
    cout << fixed << setprecision(5) << s;
    delete[] arr;
    return 0;
}